Since this morning I get an error in logfile when executing strategies manually or automatically in Strategy Monitor:

26.04.2013 10:26:25: Executing: AAPL
26.04.2013 10:26:27: Error(4): The underlying connection was closed: An unexpected error occurred on a receive.
26.04.2013 10:26:27: Executing: ABT
26.04.2013 10:26:29: Error(4): The underlying connection was closed: An unexpected error occurred on a receive.
26.04.2013 10:26:29: Executing: ACN

I tried restarting strategies, restarting WL, download data from Yahoo manually (data is ok with last bar 04/25/2013. I tried to remove and add strategies to SM after a restart of WL etc.

Is this a knwon problem? Is there a way to completely reset the SM functionality that I could start from scratch?
If I run my strategies in backtest it works as expected and alerts are shwon in Alert-Tab.
Am I able to delete some XML-Files or XML-Content to make a completely reset, which would help me in first instance.

Apparently it doesn't have to do anything with Wealth-Lab, and there's nothing to fix. It's a network stack exception caused by your network/proxy error. Simply put, it's something like a data receiving timeout (e.g. no data was returned within 100 seconds), or an error returned by Yahoo (which isn't the case as I can't reproduce it right now) etc.

If that happens on your legacy Server 2003 system (and based on the log I'm pretty sure it's the case here), ask your hosting provider's support as we can't help with this. Let them check the firewall/proxy log. Make sure that they're not limiting the number of connections in your server instance. Ensure that all patches have been applied. Consider using Server 2008 R2 instead.

Ok, I will ask my hosting provider and, but connections should then be limited in backtest modus, too.
I will restart the whole server and will verify it again. Thank you for the quick response.

Update:
After restarting the server it seems to work again. Weird problem so far ...